"Alif-Lam-Meem. (These letters are one of the miracles of the Qur'an, and none but Allah (Alone) knows their meanings.) The Romans have been defeated" (ar-Room 30:1-2): They were defeated then they prevailed. The mushrikeen wanted the Persians to prevail against the Byzantines because they were idol-worshippers, and the Muslims wanted the Byzantines to prevail against the Persians, because they were people of the Book. They mentioned this to Abu Bakr, and Abu Bakr mentioned that to the Messenger of Allah (ﷺ), and the Messenger of Allah (ﷺ) said: “They will prevail.” Abu Bakr mentioned that to them and they said: Set a deadline: if we prevail, we will have such and such, and if you prevail, you will have such and such. So they set a deadline of five years, but they did not prevail. Abu Bakr mentioned that to the Prophet (ﷺ) and he said:“Why didn't you make it within ten years?” - Sa'eed bin Jubair said: Less than ten years - Then the Byzantines prevailed after that. That is what Allah said: “Alif-Lam-Meem. The Romans have been defeated... And on that day, the believers (i.e., Muslims) will rejoice (at the victory given by Allah to the Romans against the Persians) - With the Help of Allah” (ar-Room 30:1-5).